DetermineBestParent(CGenome mum, CGenome dad)
{
if (mum.Fitness() == dad.Fitness())
{
if (mum.NumGenes() == dad.NumGenes())
{
if (Random.value < 0.5)
{
return(ParentType.Mum);
}
else
{
return(ParentType.Dad);
}
}
else
{
/*
* Choose the parent with the fewest genes because
* the fitness is the same.
*/
if (mum.NumGenes() < dad.NumGenes())
{
return(ParentType.Mum);
}
else
{
return(ParentType.Dad);
}
}
}
else
{
if (mum.Fitness() > dad.Fitness())
{
return(ParentType.Mum);
}
else
{
return(ParentType.Dad);
}
}
}
GetCompatibilityScore(CGenome other)
{
/*
* Keep track of these numbers because genomes with different
* topologies are unlikely to group together well. Therefore
* the compatability score is based on how different the
* topologies of the genomes are.
*/
float numDisjointGenes = 0;
float numExcessGenes = 0;
float numMatchedGenes = 0;
/*
* The combined error/difference between the weights of the genomes.
* A lower score means the behaviour is more probable to be
* similar.
*/
float weightDifference = 0;
CalculateTopologyDifference(out numDisjointGenes, out numExcessGenes,
out numMatchedGenes, out weightDifference,
other);
float longest = Mathf.Max(NumGenes(), other.NumGenes());
/*
* Coeffecients that are tweaked to influence the score
* roughly the same amount.
*/
const float coefDisjoint = 1.0f;
const float coefExcess = 1.0f;
const float coefMatched = 0.4f;
return((coefExcess * numExcessGenes / longest) +
(coefDisjoint * numDisjointGenes / longest) +
(coefMatched * weightDifference / numMatchedGenes));
}